The proposed research addresses the questions whether a prevention program to reduce smoking habit, blood pressure and serum cholesterol levels leads to a change in cardiopulmonary fitness; if so, whether the change is independent of a) improved mechanical efficiency on the treadmill and b) measured change in exercise habits; and if so, which risk factor reductions are associated with the improved physical performance. An ongoing study in this laboratory involves intensive intervention on these coronary risk factors in asymptomatic middle-aged men and provides an opportunity to investigate these questions which are totally separate from the methods, goals and support of that study. The proposed study is unique in that these questions have not been adequately examined under conditions in which: 1) systematic and intensive interventions are undertaken to change eating patterns, reduce blood pressure and stop cigarette smoking; 2) physical activity is specifically not a part of the intervention program; 3) change in leisure time physical activity and work capacity are carefully monitored along with other physiological and behavioral changes over time. Information provided by this project should indicate whether any changes found in cardiopulmonary fitness are mediated 1) by direct effects of the specific interventions on risk factors or 2) by indirect effects of increased physical activity, presumably related, in turn, to greater health consciousness among participants in a preventive program. This research has 1) general significance in determining their effects on risk indicators and disease manifestations.